Resettable variable radix counter



D. H. LEE

RESETTABLE VARIABLE RADIX COUNTER Oct. 1, 1957 2 Sheets-Sheet 1 FiledOct. 18, 1954 INVENTOR DONALD H. LEE BY ORNEY .Gmmm 3: 242

. humum Ebium mm mow FIIIIIIIIIIIIIIIIII Oct. 1, 1957 f D. H. LEE 2,8085 RESETTABLE VARIABLE RADIX COUNTER Filed Oct. 18, 1954 2 shee s-sheet 2INVEN TOR.

DONALD H. LEE

ATTORN EY States Unite REJSETTABLEVARIA E ADDQ COUNTER Donald Lee,"Philadelphia, "Pa,, assignor to Burroughs fiorporation,'Detroit;-Mich.,a-corporationof Michigan -Appligation October 18, 1955}, Serialfilo-462,877

Claims. (Cl.15-.j-8 5) This-invention-relates to pulse countingcircuits, and

-more particularly to resettablepulse counting'circuits includingmeansfor selectively altering the radix.

To enable high speed counting, a multi-position electron beam-magnetronswitching tube is usedof the general typedescribed in the United StatesPatent No. 2,721,-

"955;issued to'sin pih Fan and SaulKuchin'skyon 0c.-

prises a spade electrode for locking the beam. in position,

-a target electrode for receiving the beam, and a switchingielectmdearte p n he e m f om o p on to another. The spade electrodes arepositioned concentrically about the cathode and spaced apart'from eachother'to permit twoadjacent spades to define the edges ofiabean'rreceiving compartment. Thetarget electrodes are arranged concentricallyabout the spade electrodes and are positioned. to individually extendacross the spacings between adjacent ones of said spade electrodes tothereby receive substantially the entire beam passing into thecompartment. The switching electrodes are arranged concentrically aboutthe cathodeand each switching electrode is individually positioned in aseparate compartment in the vicinity of one spade electrode and thetarget electrode. A magnetic fieldis caused to permeate the tube withflux'lines substantially'parallel to the electrodes. As well known inthe art, this magnetic field in conjunction with the electric field setup between the cathode and target electrodes will cause the electronbeam to follow apath extending between two spades'when one is at a ipotential and the other is'at about the catholdepotential. As. the beamenters the compartment, part of it will bereceived by the'lowpotentialspade tohold its potential at a'low value and keep'the'beam-lockedin.

To provide switching oftheb'eam to Jthenext .compartment, the switchingelectrode is placedto alter-the beam path so that the otherwise highpotential spade receives'beam current. This'lowers the. potential of thespade enough to cause the beam to step into the adjacent compartment.The beam normally progressesfrombne compartment" to the next in thatdirection defined by the polarity of the magnetic field. 'By coupling{the switching electrodes into'two sets, each includingalternateelectrodes,fthe electron beam can be caused to advance from onecompartment to the next by changing the potential of the two sets ofswitching electrodes alternately.

This hereinbeforedescribed tube is utilized in aresettable countersystem providing a selectively variable radix in accordance with thepresent invention. 'In this system the counting may begin from somepre-selected number such as one and terminateuat any other presse lectednumber such. as two orten. Inthismanner the counter may be set for anydesired-radix. :The electron beam of the above described tube thereforecan be caused -to advance consecutivelytrom -afirstslectab1e targetatent v masses Patented Oct. 1, 1957 electrode through.-the interveningtarget electrodes to a .second selectable targetelectrodeand thenis'caused' to Iautomatically.proceeddirectly from the second'targetelectr-ode. back to the first target electrode.

A general object of theinvention is to provide'improved counter systems.

A further object of the invention is to provide variable radix countersutilizing magnetron beam switching tubes.

'Anotherobjectof the presentinvention is to'provide means whereby theelectron'beam of a multi-position electron beam switching .tube'may be'reset automatically to a particular electron beam starting position eachtime {the electron beam advances to a dilierent predeterminedbeamposition.

.In accordance'with' one embodiment of the invention,

the target electrode of a particular compartment is chosen bysele'ctor'rneans to provide a signal in response to beam impingementin'that compartment. This signal operates agating circuit which, inturn,transmits a pulse to'both the catl odean'dv that particular spadeelectrode which is chosen by further .selector means. The pulse on thecathode functions to turn off the electron beam thus .preventing it'fromsteppingfrom one target to the next until eventually arriving .atthechosen spade as it normally would "due to'the influence ofthe magneticfield Lin the sole presence of the signal to the spade. However, as thepotential of the particular spade electrode is reduced by the signalpulse in the absence of the beam and retained at reduced potential afterthe electron beam is turned on again, a' beam path between the cathodeand the chosen spade electrode is'formed causing the beam to impingeupon the chosen spade electrode, thereby holding it at reducedpotential. 1 This affords .a selective reset operation which permitsvariable radix operation with assurance that the beam will step directlyfrom one compartment to another compartment not adjacent thereto.

"To cause the beam to step from one position to the next, a countersystem is used such as described in the copending application of DonaldH. Lee for United States .Letters Patent, Serial No. 459,-697,filedOctober 1,1954. '11] this counter system the switching electrodes aredivided into two sets of alternating electrodes hereinafter'designatedas the odd numbered and even numbered electrodes. A 'feedback circuit isprovided from the target electrodes of one set'tothe switchingelectrodes of one set thereby to cause the switching electrodes of onlyone set to become primed with. internal signals dcrived from theswitching tube beam, to thereby enable an external pulse appliedcommonly to all the switching electrodes to advance the beam from "onetarget electrode to the next. In this manner t-he'beam.may bestepped asingle posiinvention.

Referring nowv to the figures simultaneously, like referencecharactersidentifysimilar component parts in orderto facilitate comparison.

The magnetron-beam switching tube is supplied with an --external:magnet8'which supplies flux lines parallel to the elongated electrodes. :Thecathode 225 is centrally located withinrthe tube envelope and "haspositioned-'ab out it three concentric {rows :of electrodes.

" -Fhe's'e elec'trodes' are respectively beam forming and holdrequiredswitching time.

ing electrodes 20 through 29 commonly termed spades,

which direct the beam to corresponding target electrodes tube 209'isnormally conducting. The beam is therefore formed and directed betweenthe low potential spade and the adjacent high potential spade so thatthe low potential spade receives enough beam current. flowing through aspade resistor40 through 49 .tomaintainits low potential and assure thatthe beam is locked in a stable position as long as statictubepotentialsiaremaintainedI The beam is moved from one stable position tothe next by means of switching electrodes 70 through 79, which areassociatedwiththe respective beam receiving compartments containingtarget electrodes 10 through 19. By decreasing the potential to theswitching electrode of any particular compartment receiving the beam,the beam isdefocussed or spread so that the normally high potentialspade receives enough offlthe beam to lower'its potential and thus causeit to transfer the beam into the adjacent compartment. By connecting theswitch- 7 ing electrodes into two sets, respectively.containing/thealternate odd and even switching'electrodes, the beam .may be made toadvance only'one compartment, even though the switchingpulse duration islonger than the The respective sets of switching electrodes for thisreason are diagrammaticallyshown in Fig. l as odd electrodes 223 andeven electrodes 222. I

' Output signals may be taken from the respective target electrodes bymeans of separate connectors which are coupled to the output terminalsTo, Ti' etc. inFig. 1.

Thus, the tube may be used as a counter or commutator.

With the operation of the tubeiin the foregoing manner in mind, thedetails of the circuit connections may be considered' The ten switchingelectrodes of Fig. 2 are represented in Fig. 1 as two-combined groups ofcommonly connected even numbered and odd numbered electrodes eachschematically represented at the terminals identified by referencecharacters 222 and 223. The cathode 225 is connected to a negativesource of potential at lead 289 as supplied at the anode of 212 ofnormally conducting tube 229. The cathode 225 is connected by analternate circuit to ground potential'through A the parallel combinationof resistance 233 and capacitor 232 connected in series with theresistance 224. The odd numbered switching electrodes 223 areconnec'ted'to the cathode 225 through series resistances 220 and 224 andthe even numbered switching electrodes 222 are .con-

nected to the cathode 225 through series resistances 221 and 224. Theodd numbered switching electrodes .223

further are connected by capacitor 283 to conductor 236 and the outputlead of a pulse standardizer circuit. contained withinthe dotted box234. The even. numbered switching electrodes are connected throughcapacitor 282 and lead 237 tothe output lead of a similanpulsestandardizer' circuit contained within the dotted box 235.

Generally speaking, the pulse standardizer circuits 234 and 235 operateto apply pulses of standard waveshape to the switching electrodes forassuring that the beam may 'be switched from onetube compartmentto thenext.

Because of input circuits connected to the pulse standardizing circuits234 and 235, only one of the pulse standardizing circuits will beoperable at any time. Each pulse standardizing circuit requires athreshold pulse of sulficient magnitude to its associated control gridelectrodes toproduce an'output signal, as will be'discussed in moredetail hereinafter."

Each of the spade electrodes20' through 29 .is ,connected to acommonregulated '-75'- volt busHliucQ238 through an individualseriescircuit comprising. one ,each' of resistances in the group 40through 49 and 60 through 69 and an inductance of the group through 59.For example, the spade electrode 20 is connected to the common bus 238through the series combination of resistance 40, inductance 50, andresistance 60. Similar circuits connect the remaining nine spadeelectrodes to the common bus bar 238, which in turn is connected to theISO volt power supply or battery source 239 through resistance 188 tomaintain the spades at a positive potential with respect to the cathode225. The inductance 50 and the resistance 6%) serve the function ofdeveloping a spade switching potential from a pulse applied to thejunction point 261 from a pulse amplifier and shaping-circuit containedwithin the dotted line 241 by way of capacitor 273, switch arm 271 andcontact 250. The switch 272 permits a negative pulse from source 241 tobe impressed upon any one of the spade electrodes 20 through 29 withsufiicient magnitude to cause the electron beam to be selectivelydirected to a corresponding compartment.- This serves as a reset signaldeveloped in response to a pulse at terminal 189 from an external source295. In order to assure that'the beam is reset without passing throughintermediate compartments, the beam is cut-off by application of thereset pulse directly to the cathode 225 along lead 289. Cut-off iseffectedby reducing the conduction of tube 209 thereby causing thecathode 225 to be nearer ground potential. I

The electron beam'can be caused to impinge upon a selected targetelectrode by two different methods in the circuit of Fig, 1. One ofthese two methods is to apply the proper'potentials to one of the spadeelectrodes 20 to 29 through the corresponding position of reset switch272 to form the beam in the compartment containing that spade electrode;The other method is to apply switching ,pulses alternately to therespective switching electrodes 222 and 223 by way of standardizingcircuit 234 or 235 to cause the electron beam to advance consecutively.from one target electrode to another. Each of the switch contacts 250through 259. are connected to an individual spade electrode through anisolating resistance of the. group 40 through 49.' As a specific examplethe contact 250 is connected through the junction point 261 and theresistance 40 to the spade electrode 20. Similarly, contacts 251 through259 are connected to the spade electrodes 21 through 29, throughresistances. 41 through 49 respectively. v

The pulse shaping circuit 241 can receive an input excitation pulse fromone of three sources. The first of these three sources isobtained'internally and is used in order to provide a ring counter. Inthis case a pulse is taken'fromoutput terminal 275 of'the counter systemas supplied by'the pulse forming circuit within the dotted line 274.Thus, a pulse is received from any target electrode which is selected bymeans of the switch within the dotted line 276. The second source is theexternal input source 295 at remote reset terminal 189'. Thethird'source comprises an internal pulse forming circuit associated withthe manual reset switch 196. V V i The pulse standardizing circuit 241is comprised of two triode sections 208 and 209 ofa 5687 type vacuumtube. The triode 208 has an anode 215, a control grid 214, and a cathode213. The control grid 214 is connected by capacitor 205 to the outputterminal 275 of the pulse.

standardizing circuit 274 through conductor 277, which 'The grid 214 isconnected to the cathode 213 through V series resistances206 and 218. Aclamping diode 207 p is connected across resistance 206. Accordingly,the

" tube 20 8 conducts throughthe grounded anode resistance 202 because ofthe negative-cathodepotential.of. about 250 volts supplied throughresistor 219, from the potential source 229.

However, the cathodes 213and1210 of :the triodes. 208

and 209 are connected together .to source229 through the' seriescombination of resistancel219 and resistance'218.

,Since the grid" 211 of tubeii209 is connected to. ground potentialthrough the resistance"204, the tube normally conducts to ground throughresistors 201 and 203. This supplies a bias potential through resistor218 which keeps current through tube 208 norrnally ata low value. Tube209\ is maintained at a safe-conduction value by grid leak bias throughresistor 204. The tap200 of variable resistance'201 is also connected,to ground potential and constitutes a-uoltage adjustment means for theplate 212 of tube'209. The plate 215 of tube 208 is connected to thegrid211 ot-tube209'through coupling capacitor 216.

through the capacitance 273 and also upon the cathode 225 of the beamposition switching tube. The coupling capacitor 216 will shortlydischarge, however, in a predetermined interval of time, thus causingthe potential of the grid 21-1 and the anode 212 of triode 109 toreturnto their initial values and accordingly end the cutoff pulse tothe cathode 225 of the beam position switching tube. However, because ofthe inductors 50 through 59, resistorsfidthrough 69, and capacitor 273,the potential at the -armature 271 ofthe selector means 272 will becomelow for a long enough time atthe end of the pulse to assure that a newlyformed beam is directed to that spadedesignated by the selected one ofswitch contacts 250 through 259.

The pulse standardizing circuits within the dotted lines 234 and 235'aresimilar and thus will be discussed to gether. It will be noted that thegrid 104 of triode tube section 101 is connectedby way-of the diode 115through one of the resistors 30, 32, 34, 36, and 38 to each of the evennumbered target electrodes. Conversely, .the grid 125 of the tube 123 ofthe pulse standardizing circuit withingthe dotted line 235 is connectedby diode 121 to the odd numbered target electrodes through resistors 31,33, 35, 37, and 39. Since the even numbered target electrodes and theodd numbered target electrodes are all connected together throughseparate load impedance devices comprising either inductor 310 andresistor 311 r inductor 312 and resistor 313, and further since theelectron beam at ,any one time will ,be impinging upon only one targetelectrode, only one of the grid electrodes 104 or 125 will be at a lowpotential due to the electron beam impinging upon one of the targets,and other grid will be a relatively high potential, Assume that theelectron-beam is impinging upon an even numbered target electrode suchas 10. Under these circumstances the grid 104 of tube 101 of the pulsestandardizing circuit within the dotted line 234 will be held at arelatively low potential. Both grids 104 and 125 are normally belowplate current cut-ofi value because of the -15 volt bias potentialcoupled thereto by resistors 113 and 122 respectively. The potential ofthe grid 125 of the tube 123 of the pulse standardizing circuit withinthe dotted line 235 however, will be relatively high and will be closerto the plate current conductive value so that there will be a platecurrent flow therein in response to a further positive pulse atcapacitor 120 as derived from source 278 at input terminal 199.

When a-pulse is transmitted-from the input source 278 it willsimultaneously be impressed uponboth the grid 1104of tube- 101 and thegrid of tube 123. However, only the plate current. of the tube 123 willflow thereby, since the grid 104 of the tube 101 is biased sufficientlybelow cut-off so that the applied pulse will not raise it above cut ofi.Consequently, of the tubes 101 and -123'on1y the potential of the plate127 of the tube 123 will'be changed due to the applied pulses fromsource 278. This decrease in potential of the plate 127 will cause acurrent flow through the winding 280 of the transformer 131. Thiscurrent will induce a voltage in the winding 281 of such a polarity thata positive pulse will be applied to the grid129 of the other tubesection 124. 'The tube 124 is ordinarily in a non-conductive conditionbecause of the -15 volt grid bias potential at resistor 137. Thepositive pulse causes the tube 124 to conduct in the manner: of othervwell known'blocking oscillators and produce a single output pulse atlead 237, which, is applied to the even z-switching electrodes .222through capacitor. 282. zThiS pulse output will causethe electronbeanrto advance from the even numbered target ;elect r,ode10 to the:next odd numbered target electrod 11 which conversely will cause.the'grid 125 of the triode ;tube 123 tobecome-biased-below cut-off andthe grid 1.04 of triode..tub e*1011 to become biased so that: asucwill,be caused to, generate a pulseat-itsanode 106 which will-be'applied-totthe-odd control grid electrodes 223 t;.throughtthe lead 236 andcapacitor-2 83.

The cathodes 103 and 108 of tubes 101 and 102 are connectedto;=ground,--potential directly and through resistance-116'respectively. Likewise the cathodes 126 and 128 of tubes 123 and124 are connected to; ground potential directly and through'resistance:13,6 respectively.

"In the outputpulse forming circuit within the dotted 'line 1274,thegrid154of tube .152 is connected for receiving aninput-@pulsefromthearmature 141 of-the :selectorswitch276. -When the armature is-makingcontact with one of thecontact buttons 142 through 151, the gridelectrode 154 :will be -at the potential of a corresp n ing r e e ec rde '1 hro O ly e resentative leads are shown connected forpurpose of,circuitsirnplicity, butyeach switch contact-iscoupledto a correspondingtarget. If the electron beam is not impinging upon a, particularselected target electrode, the potential of the grid-'154 will behigh atabout groundpotential and the tube 152 will be in a conductivecondition. Thus, theplate T'Will be at a potential considerably lowerthan that when the potential of the grid 154 is lowered to the value ofa target electrode having vthe electron beam impinging thereon. At itshigh value plate current is reduced, and by-means of a circuit extendingthrough diode158 a. positive signal is conducted to tube 166. The normalcondition of tube 166,.when

an electron beam isnot impinging on a target electrode connected to acontact means of selector means 276 with which the armature 141 ismaking contact, is cut-off because of'the 15 volts bias applied to grid167 through resistors .161, and 162. ,Whenthe plate 155 of'tube152 isinits high condition: the potential of thegrid 7167' of tube .166 which isconnected thereto through'the diode 158 is brought near groundpotential. This-will cause thetube 166-to become conducting in responsetoafur ther synchronizing pulse of positive polarity; applied by 'of thetarget electrodes.

lead 291 and capacitor 160 from input source 278. The synchronizingpulse itself is not of sufiicient amplitude to cause tube 166 toconduct, but does serve to'assure that the output pulse is timed withthe input source for synchronous operation therewith. The tube 166 isbas- 5 ically a pulse amplifier. The output pulse is not referenced toany direct current level because of transformer 180, but will appear aspositive at the upper terminal of the double pole double throw switch185. Thus, an output pulse of either polarity may be taken from terminal275. It is to be recognized that the hereinbefore described ring-countaction necessitates a positive pulse at lead 277, but for other outputconditions a negative pulse might be convenient. Diodes 181 and 184serve to shape the pulse and isolate the circuit from an external load,re'-' circuit of Fig. 1 is made hereinafter with the assumption that itis desired to have the electron beam cycle from the 3 position targetelectrode, through the intervening target electrodes to the 8 positiontarget and then directly back to the 3 position target electrode tobegin the cycle again. selector means 272 is set to'make contact withcontact 253 which is connected to the 3 position spade electrode 23through resistance 43. The armature 141 of the scale selector means 276is set to make contact with the contact 150 which is connected to the 8position 5 target electrode 18. a

The electron beam may initially be impinging upon any In order to startthe electron beam upon the 3 position target electrode the manual resetbutton 196 is depressed thus closing the lower con- 40 tacts andpermitting the capacitor 198 to produce a reset pulse. This pulse isimpressed upon the grid 214 of the tube 208. This results in a positivepulse at the plate 212 of triode 209 which is connected directly to thecathode 225 of the beam position tube and also to the arma,

ture 271 through the capacitor 273. This pulse applied a to the cathode225 of the beam switching tube will extinguish the electron beam. Thepulse applied to the armature 271 can be traced further through thecontact 253 and the resistance 43 to the spade electrode 23. Thepotential of the spade electrode23 will, when the pulse is first appliedthereto from the pulse standardizing circuit 241, increase in a positivedirection without effect on the beam formation. However, at theexpiration of this pulse when the cathode is returned to operatingpotential, the potential of the'spade electrode 23 will decrease becauseinductor 53, resistor 63 and capacitor 273 and the spade electrode 23will tend to assume a negative potential. The reformed electron beamwill therefore be caused to flow to the spade electrode 23 due to thedecreased potential thereon, and will be locked into position because ofbeam current through resistor 43."

When the electron beam impinges on the spade electrode 23, it alsoimpinges on the associated 3 position target electrode 13. The targetelectrode 13 is an odd 65 numbered target electrode and all 0tv the oddnumbered target electrodes are connected to a common bus bar 288 whichin turn is connected to the grid 125 of tube 123 through theasymmetrical device 121. Thus, the grid 7 125 of tube 123 is biased wellbelow plate current'cutoff' value. On the other hand, the grid 104 ofthe tube 101 which is connected to the even numbered targetelectrodesthrough the asymmetrical device 115 is biased only about ten volts belowcutoff. Thus, when a thirtyvolt positive pulse is impressed uponthegrids 104 and 12 5;

Each of the neon tubes has one of its -20 The armature 271 of the reset30 of tubes .102 and 123 from the input pulse source 278,

the grid potential of tube 123 will not be raised above the platecurrent cutoif value but the. potential of the grid 104 of the tube 101will cause the tube to form a pulse. Consequently, there will be anegative pulse generated at' the .plate'106 of tube 102 and transmittedto the odd numbered switching grid electrodes 223 through the conductor236 and the capacitor 283. No corresponding pulse will be transmitted tothe even numbered control grid electrodes. When the pulse is applied tothe odd numbered switching grid electrodes 223, the electron beam willbe caused to advance from the odd numbered 3 position target electrode13 to the even numbered 4 position target electrode 14. Thus, when theelectron beam impinges upon the target electrode 14 conversely thepotential of the grid 104 of the tube 101 is decreased to a value farbelow cut-oil since the grid 104 is connected to all of the evennumbered target electrodes by diode at bus 287. The potential of thegrid of the tube ,123 is similarly increased to a value just below platecurrent cut-oflf potential. When a positive pulse is now appliedsimultaneously to the grids 104 and 125 of tubes 101 and 123 from source278 there will be a negativ'e'output pulse generated at the plate of thetube 124 which will be impressed upon the even numbered switching gridelectrodes 222 through the conductor 237 and the capacitance 282. Thiswill cause the electron beam to advance from the even numbered targetelectrode 14 to the odd numbered target electrode 15 which will producethe same conditions with respect to the pulse standardizing circuits 234and 235 as when the electron beam was impinging upon the odd numberedtarget electrode 13. Subsequent pulses from the input pulse source 278will cause the electron beam to continue to advance along consecutivetarget electrodes until it reaches the "8 position target electrode 18.

a As has beendiscussed hereinbefore, the electron beam will be'impingingsimultaneously upon the 8 position target electrode 18 and also upon the8 position spade electrode 28. *Thus, the potential of target electrode18 is low and is impressed upon the grid'154 of the triode tube 152through a circuit extending from the target electrode 18, the conductor269, the contact button of the scale selector means 276, armature 141,the parallel combination of resistance 139 and capacitor 140 to the grid154 of the triode 152. The plate current of the triode 152 is cut-offthereby and the potential of the plate 155 thereof is caused to increaseto ground potential by action of the diode 159. Under these conditionsthe controlgrid 167 of the pentode 166 can rise to conduction potentialin the presence of a subsequent trigger pulse at input terminal 199.Howeven-until target 18 becomes 'low, the tube 152 is conductiveand the214 of the triode 208. This'pulse is of the proper magnitude-to generatea pulse at the plate 212 of tube 209 in a manner described hereinbeforewhich will cause the electron beam to impinge upon the 3 positiontargetelectrode 13 in the same manner as described at the beginning of thedescription of operation. Thus, a variable scale count is eltected witha reset to any desired tube compartment from any other desired tubecompartment. V V

It. is to be observed that the pulse from the input source 278 thatcaused the electron beam to go from the 8 position target electrode 18to the 3 position target electrode 13 is the same pulse that would causethe elec-C tron beam to advance to the 9 position target electrode 19from the 8 position target electrode 18 with the scale selector 276 setfor decimal counting, However, due to the fact that the pulsetransmitted from the circuitry within the dotted line 274 in turn causesa pulse to be transmitted from the circuitry within the dotted line 241of the cathode 225 to cause the electron beam to be cut-off, the timerequired for a pulse to be impressed upon the cathode 225 and cause thebeam to advance is longer than the time required for the electron beamto advance from one target electrode to another target electrode in theintermediate steps. Consequently, the counter speed is lower when thereset feature is used than when the tube is used for freely counting ina repetitive closed loop established by tube electrodes alone.

If at any time during the operation of the device it is desired to resetthe electron beam to the position selected by the selector means 272such a function can be obtained in one of the three hereinbeforedescribed methods. Assume that the selector means 272 and 276 are setfor counting from 3 to 8 and that the electron beam is impinging uponthe 6 position target electrode 16. If now a positive pulse is appliedto the remote reset terminal 189 from the external pulse source 295, thegrid 214 of the tube 208 will be caused to become positive which willgenerate a positive pulse at the plate 212 of tube 209 in a mannerdescribed hereinbefore which will cutoff the electron beam and furtherwill cause the potential of the "3 position spade electrode 23 to besufficiently negative at the termination of the pulse from the plate 212of tube 209 to cause the electron beam, when reformed, to be in the 3compartment.

Likewise, if the manual reset switch 196 is depressed to close the lowercontacts, the capacitor 198 will discharge to transmit a pulse throughdiodes 193 and 190, and capacitor 205 to the grid 214 of the tube 208 tosimilarly cause the electron beam to be turned off and then be reformedon the 3 position target electrode.

Novel features and advantages contributed by the invention are to berecognized from the foregoing detailed description of its organizationand operation. Those features believed descriptive of the nature andscope of the invention are therefore defined with particularity in theappended claims.

What is claimed is:

1. A resettable variable scale counter system comprising in combination,a multi-position magnetron beam switching tube having a plurality ofoutput target electrodes each defining beam receiving compartments forone of the beam positions and beam holding electrodes connected forholding the beam in position in each compartment, inductance meanscoupled to the beam holding electrodes for selectively forming the beamin any particular one of said compartments in response to a positiveelectronic signal and means for selectively cycling the beam from anychosen one of said compartments directly to the compartment at which thebeam is formed and successively from one compartment to another to thechosen one of said compartments in response to successive input pulses,the latter means including a feedback loop from the chosen compartmentto the particular compartment at which the beam is formed.

2. A system as defined in claim 1 wherein the system includes an outputcircuit having a triggered pulse forming device in said loop, andseparate output circuits from each of the target electrodes.

3. A system as defined in claim 1 including means for stepping the beamsuccessively from one position to the next in response to successiveinput pulses comprising switching electrodes in said tube, a pulseforming device responsive only to a combination of internal signalsderived from the beam positioning upon an electrode and an externaltrigger signal, and a circuit coupling said pulse forming device toselected switching electrodes.

4. A resettable counter system having a multi-position magnetron beamswitching tube with a cathode and a beam forming electrode comprising incombination, means for passing a positive pulse simultaneously to thecathode and beam forming electrode, the circuit parameters beingselected so that the pulse amplitude at the cathode is sufficient toextinguish the beam, and inductance means responsive to the expirationof the positive pulse to cause the beam forming electrode to pass into anegative excursion, whereby the beam is reformed at the beam formingelectrode.

5. Means for providing a number of consecutive beam positions in amulti-position magnetron beam switching tube less than the number ofconsecutive electrode positions available in the tube comprising, incombination; an equal number of beam forming, beam switching and beamreceiving electrodes respectively disposed in corresponding beamreceiving positions in said tube; means coupled to the beam switchingelectrodes to step the beam from one consecutive position to another,means coupled to one beam receiving electrode to produce an outputsignal pulse, means coupled to one beam forming electrode in anon-adjacent beam position to said one beam receiving electrode toreduce the beam forming electrode potential in response to said outputsignal pulse, and means coupled to said tube to extinguish the beam inresponse to said output signal pulse during a time period expiring Whilethe beam receiving electrode potential is still reduced by the etfect ofsaid output signal pulse.

References Cited in the file of this patent UNITED STATES PATENTS2,137,262 Bowman-Manifold Nov. 22, 1938 2,222,943 George Nov. 26, 19402,361,766 Hadekel Oct. 31, 1944 2,488,452 Van Overbeek Nov. 15, 19492,620,454 Skellett Dec. 2, 1952 2,706,248 Lindberg Apr. 12, 1955

